Most developers do just fine as long as they don’t stumble on things like PKI, RSA, PKCS#1, X509, CRL, OCSP, and such. We start the presentation within an overview of the Belgian eID card and its capabilities. We also detail on the PKI infrastructure supporting the eID. Next we take a look at the different options on integrating eID within your (web) applications and we highlight the new Commons eID library. We present its architecture, design choices, and JCA integration, to end with some eID coding.